Fix typos in the notes

688-674 is clearly wrong, but it seems just as likely that it's a typo of
668-674 as the range being reverted, so leave it as it is in the book.

Note 10.49 was missing completely.
Fix unbalanced (as in book) quotes in the notes

I'm not positive that it's now correct, but there's a good chance.
Contract . . . to ... in the notes